Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Quais políticas foram implementadas em 'Delhi' ou 'Mumbai' entre 2018 e 2021?
 ###Tabelas: 
CREATE TABLE City (id INT, name VARCHAR(50)); INSERT INTO City (id, name) VALUES (1, 'New York'); INSERT INTO City (id, name) VALUES (2, 'Los Angeles'); INSERT INTO City (id, name) VALUES (3, 'Delhi'); INSERT INTO City (id, name) VALUES (4, 'Mumbai'); INSERT INTO City (id, name) VALUES (5, 'Tokyo'); CREATE TABLE Policy (id INT, name VARCHAR(50), city_id INT, category VARCHAR(50), budget DECIMAL(10,2), start_date DATE, end_date DATE); INSERT INTO Policy (id, name, city_id, category, budget, start_date, end_date) VALUES (1, 'Education', 3, 'Education', 1200000, '2021-01-01', '2023-12-31'); INSERT INTO Policy (id, name, city_id, category, budget, start_date, end_date) VALUES (2, 'Healthcare', 3, 'Healthcare', 1500000, '2020-01-01', '2022-12-31'); INSERT INTO Policy (id, name, city_id, category, budget, start_date, end_date) VALUES (3, 'Transportation', 4, 'Transportation', 2000000, '2019-01-01', '2024-12-31'); INSERT INTO Policy (id, name, city_id, category, budget, start_date, end_date) VALUES (4, 'Education', 4, 'Education', 1800000, '2020-01-01', '2023-12-31');
SELECT name, start_date FROM Policy JOIN City ON Policy.city_id = City.id WHERE City.name IN ('Delhi', 'Mumbai') AND YEAR(start_date) BETWEEN 2018 AND 2021;